1. Field of the Invention
The present invention relates to an optoelectronic panel which has at least a liquid crystal display device and a photo detecting device formed on a common substrate. The invention also pertains to a method for the manufacture of such a panel.
2. Description of the Prior Art
Heretofore there has been proposed a display panel which employs m.times.n (where n.gtoreq.1 and m.gtoreq.1) liquid crystal display devices D.sub.11 to D.sub.1n, D.sub.21 to D.sub.2n, . . . and D.sub.m1 to D.sub.mn.
In this display panel, a liquid crystal element C.sub.ij (where i=1, 2 . . . m; j=1, 2 . . . n) is connected via a nonlinear element H.sub.ij to a row line x.sub.i and a column line Y.sub.j at their intersection.
With such a display panel, an image display can be provided by driving the liquid crystal elements at the intersections of selected ones of row lines x.sub.1 to x.sub.m and column lines Y.sub.1 to Y.sub.n through the selected lines.
The conventional display panel employs insulated gate FETs as the nonlinear elements. The manufacture of the insulated gate FET calls for many steps using as many as six to eight photo masks.
Accordingly, the conventional display panel cannot be fabricated with high production yield, with ease and at low cost.
Furthermore, there has been proposed a write panel which employs m.times.n pressure-sensitive elements K.sub.11 to K.sub.1n, K.sub.21 to K.sub.2n, . . . and K.sub.m1 to K.sub.mn and in which the pressure-sensitive element K.sub.ij (where i=1, 2, . . . m and j=1, 2, . . . n) is connected between a row line X.sub.i and a column line Y.sub.j at their intersection.
With such a panel, by a pressurized write thereon by a pen or similar means, the coordinates of its locus on the panel can be output on the row and column lines X.sub.1 to X.sub.m and Y.sub.1 to Y.sub.n.
It is difficult, however, to press the pressure-sensitive elements under the locus with a predetermined value, and the pressure-sensitive elements are easily fatigued and are relatively low in response speed.
Accordingly, the conventional write panel is defective in that the coordinates of a locus of a pen or the like cannot be output on the row and column lines with high reliability and at high speed.
Moreover, there has not been proposed a highly useful panel which has the functions of both a display panel and write panel. Conventionally, it is therefore necessary to employ a display panel and a write panel for obtaining the both functions.